A communication system is known which includes an MFP (abbreviation of Multi-Function Peripheral), a mobile terminal, and an IC card. In this type of communication system, in a case where a communication partner is the mobile terminal, a P2P (abbreviation of Peer to Peer) communication link is established, and consequently the MFP performs a function complying with a function performing instruction received from the mobile terminal. On the other hand, in a case where the communication partner is the IC card, a Reader-CE (abbreviation of Card Emulation) communication link is established, and consequently the MFP performs a login process by using a user ID received from the IC card.